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Hi everyone,

I am considering an industrial AC motor for my EV project. I have more or less decided on the controler specs and motor output.

One of the more frequent discussion on the forum is the voltage level of the system. Ideally, i would like my system to work close to standard ~230V rms (at least in my country) phase voltage. This would need DC bus levels of ~325V, which is ok. The reason is:
  • Most electrical equipment is built for these voltage levels: cables, contactors, switches, fuses etc.
  • It offers good balance between efficiency of the whole system and safety.
  • I am familiar with these voltage levels.
Higher voltages could be more beneficial efficiency vise, but probably not much to matter. Also, I would not like to encounter some clearance and isolation isues that are mentioned on this forum.

I have found a nice little motor for my project. It is Lenze MF series, optimised for inverter operation. Some data on the motor:
  • 4 pole
  • 18.5kW (25HP) at 360V/120Hz star (3600 rpms)
  • 66 kg
This is the same motor that Johannes Hubner used for his EV project very successfully (Open_source_inv).
Finally the issue at hand. The motor has very peculiar winding connection, since it is connected in star and there is no possibility to change it outside. Only three terminals are avaiable (U1,V1,W1).
To power this motor as it is would require 500V+ DC bus to drive it at its nominal power, which is to high for the reasons given earlier. However, if this motor could be driven in delta, that would require only ~300V dc voltage. The manufacturer doesn’t offer such modifications for simple mortals, unfortunatelly.

Did some of the esteemed DIY builders have experience with motors in such configurations (or this model particularly)?

How complicated would be to extract other phase endings (U2,V2,W2) to motor connector?

In addition to last question, is there some winding arrangement where the complementary phase terminals (U2,V2,W2) are not easily approachable which would make this experiment impossible?
 
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